Knockdown chair



March 1953 P. c. cuRTls KNOCKDOWN CHAIR Filed July 10, 1951 INVENTOR a ATTORNEY Patented Mar. 24, 1953 UNITED STATES PATENT OFFICE.

KNOCKDOWN CHAIR Philip. Curtis, Scottsdale, Ariz.

' Application July 10, 1951, Serial No. 235,955

2 Claims.

experienced in attempting to provide simply constructed, inexpensive chairs from materials readily available, wherein the use of external fasteningimembers such as bolts, nails, rivets, glue or the like could be dispensed with. It has been commonly accepted that such elements are essentia1 "parts of every good chairs construction.

Whenever such fastening elements were absent in a chairs construction, the several parts were usually never secured or joined together satisfactorily and the chair was always structurally weak. After a few months or weeks use, one or more elements ofthe chair would become loose and disengaged from a second cooperating member. The chair was then rendered useless until it could be satisfactorily repaired.

Furthermore, the chairs of the past which have been so designed that they could be assembled without the use of external fastening elements, ordinarily contained parts of such a complex nature and intricate design that expensive fabricating equipment was required for their manufacture. Special skills were also required by those charged with assembling the parts to form the finished product, with the net result that extensive manufacture and. sale of such chairs was neither commercially feasible or practical, because of the expense involved.

In addition the design and manufacture of such chairs was ordinarily limited to chairs made of metal, since the elimination of suitable external fastening elements meant that the chair parts themselves had to serve as their own fastening elements and this could be accomplished satisfactorily only by the use of metal parts. This again was another factor adding to the overall expense of the chair.

. It has been found, however, that by properly .designing the several parts of a chair, so that one part will suitably interlock with another part, a rigid and exceptionally strong chair is provided which can be readily and cheaply manufactured, and which can be assembled quickly and without the requirement. of any exceptional skill or tools. The chair of the instant invention also has such inherent strength and rigidity because of the design of the severalinterlocking parts that these parts can be made from either wood or metal. The chair can also be sold in small, convenient packages.

It is a primary object of this invention, therefore, to provide a novel chair assembly having interlocking parts, which serve as their own fastening elements in and of themselves.

Another object of this invention is to provide a novel chair assembly having parts which can be inexpensively manufactured.

Another object of this invention is to provide a novel chair assembly which has such inherent strength and rigidity because of the design of the several parts thereof that in can be easily fabricated from thin plywood.

Another object of this invention is to provide a novel chair assembly having parts which can be easily put together without the necessity for exceptional skill.

A further object of this invention is to provide a novel chair having parts which lend themselves to easy and quick assemblage or dismantlement and which prior to assemblage or after dismantlement can be placed in a small convenient package or container which can be stored in a minimum amount of space.

Another object of this invention is to provide a chair construction wherein the use of such fastening elements as nails, bolts, screws, glue, etc, can be dispensed with.

These and other objects will become more apparent by reference to the following detailed description when taken in conjunction with the drawings wherein:

. Figure l is a perspective view of the chair assembly' of the instant invention;

Figure 1A is a perspective view partly broken away of a modified form of back construction for the chair assembly of Figure 1;

Figure 2 is a sectional view ofthe chair assembly shown in Figure 1, when taken along lines 2-2 of Figure 1;

Figure 3 is-a bottom plan view of the chair assembly shown in Figure 1;

Figure 4 is an exploded view of the chair of Figure 1, showing the relationship of the several interlocking parts thereof prior to assembly;

Figure 5 is a side elevational view of a J- shaped base member used in the chair assembly of Figure l; and

Figure 6 is an enlarged side elevational view .of one-half of a transverse bridging member used in the construction of the chair. H By referring to the drawings and particularly Figures 1, 2, '4 and 5, it will be observed that the chair assembly of the instant invention contemplates the use of a pair of roughly J -shaped base members I, one for each side of the chair. Each J shaped base member is so formed from a single piece of suitable material, such as plywood, so as to be provided with a. short front leg '2, a floor engaging web portion 3 and a back leg l which is substantially longer than the front -leg, the upper part of this back leg serving as a post to which a suitable back plate or rest 5 may be removably attached in a manner to be described later.

Each of the front and back legs 2 and t of each J-shaped member have upper free ends which terminate in a pair of spaced upwardly projecting fingers 6 and 6. Each back leg 4, as will be observed, is also advantageously provided intermediate the ends thereof with an inwardly projecting shoulder portion 7!. Located within this shouldered portion is a downwardly inclined, diagonal slot or groove 8. A second inwardly projecting slot or groove 9 is spaced a suitable distance upwardly on leg 5 from slot 8.

A suitable inverted U-shaped dowel or transverse'bridging member it made from a single piece of material in the same manner as base members I is interposed between and about the shoulder portions 1 of each back leg in the following manner; Each dowel or bridging member I is so formed as to be provided with a web portion ll both free ends of which terminate in downwardly projecting bifurcated arms i2. When the slotted shoulder portions 7 of each leg 4 at the point of the slot 8 therein are snugly inserted substantially at right angles between the bifurcated arms [2 and dowel it is moved downward until the bases it of the slots H in arms [2 contact the bases 8' of the slots 8 in legs 4, arms l2 and legs t are rigidly interlocked with each other.

A second inverted U-shap-ed bridging member l3 also made from a single piece of material is disposed in a similar manner as bridging member l6 between the front legs 2 of each J -shaped member. Bridging member I3 is comprised of a web portion I both free ends of which terminate in downwardly projecting bifurcated arms It. The upwardly projecting fingers '6 of each front leg 2 are adapted to snugly interlock substantially at right angles with the bifurcated downwardly projecting arms I of bridging member I 3 when member I3 is moved downward until the bases 13' of the slots It in arms M come into contact with the ends l5 of the slots i5 located between fingers *5 of the front legs. Thus when dowel member W is interlocked with back legs 4 and bridging member i3 is interlocked with front legs =2 a suitable strong and rigid foundation is provided for a seat member it which is adapted to be mounted thereon, when the back marginal edge of the seat is inserted in slots 9 in legs 4 of the J-shap-ed base members.

It will be further observed by referring to Figures 2 and 4 that the top web portion i5 of bridging members 13 may be made in the form of an upwardly projecting longitudinal shoulder [7, which is adapted to engage a hollowed out recessed portion l 8 in the underside of seat member I 6 adjacent the front marginal edge thereof. The inside face I9 of web [*5 of the bridging member I3 may also be provided with a hollowed K bout recessed portion 2!], within which a latching lug 2|, pivotally attached to the underside of seat L6. may be inserted so as to serve as additional locking means for anchoring the seat 1-6 to bridging member [3. advantageously be made from plywood scraps.

With respect to the seat It the back edge of this seat element may also be provided, if desired, with a pair of spaced inwardly projecting grooves or slots 22, which are adapted to interlock with slots 9 on leg elements 4 at substantially right angles thereto to insure the anchoring of seat It to back legs 3. The locking of the seat element to the legs A also causes the several bridging members to lock securely with the J- shaped members.

To finally complete the chair assembly it is only necessary to insert the side edges 25 and 26 of a back rest 5 between the (lingers 5' located at the upper free ends of back legs 3. Suitable slots 38 may also be provided parallel with and adjacent to the marginal side edges 25 and 26 of the back rest 5, if desired, which will then allow the back rest to be moved downward until the bases 2-8 of the slots 30 therein meet the ends 29 of the slots 3| provided between fingers *6 in arms d.

This back rest 5 as will be observed by referring to Figure 1A may be of any desirable size. It is also contemplated that by making minor changes in the design of the seat l6 and legs l of the J- shaped members, that suitable arms could also be provided for the chair.

it will be noted that the use of the floor engaging webs 3 on the J-shaped members perni-its an equal amount of upward thrust to .be placed on each of the legelements 2 and l; The use of webs H and if: in the transverse bridging members allows an equal amount of downward thrust to be placed on the downwardly projecting arms l2 and Hi, all of which provides for a sturdier chair.

It will also be observed that the various parts of the chair are so fabricated that they provide their own fastening elements. By using such an interlocking arrangement for joining the several members together, each member serves to reinforce the adjacent or interlocked member and a strong, sturdy chair is provided, without the use of external fastening elements such as nails, screws, clamps, etc.

The interlocking joints make assembly and dismantlement of the chair a simple matter and no tools are needed. The parts are also subject to being easily stored in a minimum amount of space and it can be easily and cheaply manufactured.

Although the preferred embodiment of the invention contemplates that each of the several parts of the chair be made of readily obtainable materials such as plywood, which can also be cheaply and conveniently shaped, it is also within the contemplation of the invention that other materials could be used.

Furthermore, although plywood having a thickness of about W4 of an inch is the usual size of plywood employed in the making of furniture of this kind, it has been found that because-of the inherent strength and rigidity afforded the chair because of the interlocking arrangement of the several parts or sections of the chair of the instant invention, and the web portions provided for the J-shaped members, and bridging and dowel members, that plywood having a thickness within the range of to of an inch can also be used with excellent results for all the parts. In practice plywood of /2 of an inch thickness has been found advantageous. This savings in This latching lug may material is obvious and can in turn be passed on to the consumer.

The simplicity andease of assembly is an essential characteristic of the chair design. It is so simple to assemble that even a child can do it.

All of the parts fit firmly together, the various slots and openings in the several parts being only of sufficient width to snugly accommodate the member adapted to be inserted therein. In this way the chair can be lifted or carried about without the various elements coming apart.

Various other changes and modifications can be made in the invention without departing from' the spirit and scope thereof as defined by the appended claims, wherein what is claimed is:

1. A chair construction of the type described comprising the combination of a pair of spaced upright base members, each one of which is so formed from a single piece of material as to be provided with a floor engaging web portion, a

relatively short leg element projecting upwardly from one end of said web portion, the free end of said leg element being bifurcated, a second leg element of greater length than said first leg element projecting upwardly from the other end of said web portion, the free end of said second leg also being bifurcated, and said second leg element also having a shoulder portion intermediate the ends thereof, said shoulder portion in turn being provided with a downwardly and inwardly projecting slot, an inverted U-shaped dowel member having bifurcated free ends which are adapted to interlockingly engage the slotted shoulder portions of the second leg element of each base memher, a bridging member having a web portion provided with a longitudinal slot on the inner face thereof, and downwardly projecting arms at each end thereof, the free ends of said arms being bifurcated, said bifurcated free ends of said last mentioned arms being adapted to interlockingly engage the bifurcated free ends of said first men tioned leg elements on each of said base member, a seat member mounted upon said dowel and said bridging members, said seat member having a pair of spaced slots on the back marginaledge thereof, within which the second mentioned legs of the base member are adapted to be inserted and said seat member also having a latching lug pivotally attached to the underside thereof and insertable within the longitudinal slot located on the inner face of the web of said bridging member, and a back member for said chair, the bottom portions of which are adapted to be interlockingly engaged by the bifurcated free ends of said second mentioned leg elements on the said base member.

2. A chair construction of the type described comprising the combination of a pair of upright, spaced J-shaped members, each of said members having a short front leg and long back leg, each of said front and back legs having upper free ends terminating in spaced upwardly projecting fingers, and each said'back leg being provided intermediate the ends thereof, with an inwardly projecting slotted shoulder portion, a dowel member interposed between the shoulder portions on the back legs of said J-shaped members, and having downwardly projecting bifurcated free end portions which interlock at right angles with the slotted shoulder portions of said back legs, a bridging member interposed between the front legs of said J-shaped members, and having downwardly projecting bifurcated free end portions which interlock with the said upwardly projecting fingers on the said front legs and said bridging member also being provided with an upwardly projecting shoulder portion, and a longitudinal hollowed out recessed portion spaced a short distance downwardly from said shoulder portion and in parallel relationships therewith on the inner face of said bridging member, a back plate having ends adapted to be removably inserted between the fingers on the free ends of each of said back legs and a seat member mounted-upon said dowel and said bridging member, said seat member having a pair of spaced slots in the back edge thereof within which the intermediate parts of the back legs are adapted to be inserted, said seat also having on the underside thereof a hollow recessed portion adjacent the front marginal edge thereof and a latching lug pivotally attached to the underside of said seat in spaced relationship to said recessed portion, said latching lug being insertable within the recessed portion of said bridging member and said shoulder portion of said bridging member being insertable within the recessed portionon the underside of said seat when said seat is mounted on said bridging member.

PHILIP C'. CURTIS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS C'enis Dec. 19, 1950 

